Technical Abstract:
Although urbanization has a major impact on watershed hydrology, there have not been studies to quantify basic hydrological relationships are altered by the addition of impervious surfaces. The USDA-ARS and USEPA-ORD-NRMRL have initiated a pilot program to study the impacts of different extents and geometries of simulated impervious surfaces on hydrologic balance in 0.75 ha experimental subwatersheds located at the North Appalachian Experimental Watershed, Coshocton, OH. The foundational work has been conducted with rainfall simulation in soil boxes at USDA-ARS-NSERL in order to test for the effects of generic impervious surface cover between 5 and 40 percent, under two geometric progressions representing stream-channel-connected versus stream-channel unconnected imperviousness. The results from this laboratory simulation will be used to scale implementation of impervious surface in 0.75 ha sub-watersheds. The proposed experimental approach makes full use of USDA-ARS watershed experimental stations, and the historic baseline data that is available from these sites. Results from this study are applicable to the development of urban hydrology and water quality models, improved capacity for supporting hydrologic paradigm in urban watershed planning, design and testing of urban best-management practices, and environmental management.